Authors:

None are known to be good, till they have opportunity to be bad.

Benjamin Whichcote, Anthony Tuckney (1753). “Moral and religious aphorisms [collected by J. Jeffery from the papers of B. Whichcote]. Now re-publ., with additions, by S. Salter. To which are added, Eight letters: which passed between dr. Whichcote, and dr. Tuckney”, p.84
None are known to be good, till they have opportunity to be bad.